Problem: Simplify the following expression: $k = \dfrac{2z^2 + z}{yz - 2xz} + \dfrac{yz + z}{yz - 2xz}$ You can assume $x,y,z \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{2z^2 + z + yz + z}{yz - 2xz}$ $k = \dfrac{2z^2 + 2z + yz}{yz - 2xz}$ The numerator and denominator have a common factor of $z$, so we can simplify $k = \dfrac{2z + 2 + y}{y - 2x}$